From community to transcriptome: Responses of Syntrichia caninervis and biocrusts to climate change

Rengifo Faiffer, Maria Cristina (2021) From community to transcriptome: Responses of Syntrichia caninervis and biocrusts to climate change. Doctoral thesis, Northern Arizona University.

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Abstract

The increasing temperatures and severity of droughts are modifying dryland ecosystems worldwide and reducing the provision of ecosystem services in the home of about 3 billion people. Biological soil crusts (biocrusts) - assemblages of cyanobacteria, lichen, fungi, bryophytes and other organisms - are major contributors to the functionality of surface landscape features in the Southwestern USA. Here, we investigated how biocrust communities and one common biocrust moss species, Syntrichia caninervis, will respond to climate disturbances, to better understand and predict global change impacts on drylands biodiversity. This dissertation explores the climate disturbance impacts across organizational scales in biocrusts, examining the responses of the community, moss population morphological traits and transcriptomic profiles. To better understand the effects of long-term induced drought on the composition and maturity development of biocrusts, we conducted a community structure survey on sites with 8 years of rainfall reduction across an aridity gradient in the Colorado Plateau region in the Southwestern USA. We tested the hypothesis that higher diversity promotes stability using the compositional resistance as a measure for ecosystem stability. We found biocrust communities to have lower later successional moss cover and an increased early successional cyanobacterial cover, despite an overall similar species composition with the control plots. In addition, we found richer communities to be more susceptible to greater change in their composition, not less, refuting our hypothesis. To understand how populations of dryland moss respond to altered climatic conditions, we explored the changes in Syntrichia caninervis morphological traits and transcriptomic expression in altered environments. Phenotypic plasticity is often thought of as a rapid-response mechanism by which one genotype can express varying phenotypes when exposed to different environmental conditions. Phenotypic plasticity is observed throughout the life of an organism and could allow it to survive in novel environments. For plant species, plastic phenotypic changes of morphological and physiological traits are mostly controlled by gene expression. We used two reciprocal transplant experiments at the community and species level in a natural elevational gradient, and the previously mentioned 8 year community multi-site rainfall reduction experiment on the Colorado Plateau to test the hypotheses of morphological variability and phenotypic plasticity in response to novel climates. We found climate-driven phenotypes that present rapid morphological plasticity to climate disturbance, supportive of our hypothesis. Despite the influence of population provenance in the levels of plasticity, most of the changes that occurred after one-year in the novel environments appear non-adaptive and may or may not be advantageous to the persistence of the species. Finally, we ask if novel climates induce change in the transcriptomic profile in S. caninervis populations across an elevational gradient, we compared whole-genome transcriptome profiles of S. caninervis from the two reciprocal transplants. We found a clear pattern of differential transcript abundance driven by the environment, that could be linked to the (1) time of acclimation, (2) directionality of the climate change and/or (3) influenced by biotic interactions. These results confirmed the knowledge of Syntrichia caninervis phenotypic plasticity and its potential for adaptation; however, the lack of detectable transcriptomic plasticity after one year in response to climate stresses could potentially be a disadvantage in the persistence of the species in scenarios of rapid and/or erratic climate changes.

Item Type:	Thesis (Doctoral)
Publisher’s Statement:	© Copyright is held by the author. Digital access to this material is made possible by the Cline Library, Northern Arizona University. Further transmission, reproduction or presentation of protected items is prohibited except with permission of the author.
Keywords:	Biocrusts; Ecological genetics; Ecological stability; Phenotypic plasticity; Trait ecology; Southwest (U.S.)
Subjects:	Q Science > QH Natural history
NAU Depositing Author Academic Status:	Student
Department/Unit:	Graduate College > Theses and Dissertations College of the Environment, Forestry, and Natural Sciences > School of Forestry
Date Deposited:	14 Feb 2022 18:14
Last Modified:	14 Feb 2022 18:14
URI:	https://openknowledge.nau.edu/id/eprint/5695

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